A preliminary assessment of the BL situation on Dagestan’s breeding farms was conducted in 2002. Official statistics from January 1, 2002, reported 14 breeding farms in the region, maintaining a total cattle population of 13,411, which included 4,955 cows. The findings on the spread of BL and BLV on these farms are presented in Figures 1 and 2.
Fig. 1. The BLV infection rate on the breeding farms in the Republic of Dagestan in 2002 (%)
Fig. 2. The BL incidence rate on the breeding farms in the Republic of Dagestan in 2002 (%)
Our analysis established a widespread distribution of BL at the start of the study period. Among Dagestan’s breeding farms, the BLV infection rate in susceptible animals varied considerably, ranging from 2.2% at agricultural cooperative “Plemkhoz Kulinsky” to 83.5% at agricultural cooperative “Novochirkeysky”. Similarly, BLV incidence rates ranged from 2.3% (agricultural cooperative “Druzhba”) to 19.0% (agricultural cooperative “Novochirkeysky”), with average rates of 32.2 and 10.4%, respectively.
Serological testing coverage for BL was 37.9%, while hematological testing covered 25.8% of the total cattle subjected to diagnostic screening.
A comparative epizootological assessment revealed a more intense epizootic process caused by BLV on breeding farms compared to commercial and backyard farms, with infection rates of 29.7, 24.7, and 7.9%, respectively [
Thus, determining the BLV prevalence rate in cattle and clinical severity of BL on breeding farms through systematic diagnostic testing became imperative. To this end, the dynamics of the BLV infection rate were assessed annually from 2009 to 2017 across an average of 11–19 farms (Table 1).
Table 1
Dynamics of BLV infection on the breeding farms in the Republic of Dagestan in 2009–2017
“–” – there was no data on the status of the breeding farm.
| Breeding farms | Number of BLV-carriers identified, % | Total number for 9 years, % | ||||||||
| 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | ||
| Joint-stock company "Kizlyaragrocomplex" | 47.6 | 37.9 | 0 | – | – | – | 0 | 12.6 | 44.1 | 39.9 |
| Company “Plempredpriyatiye Elita” | – | 54.1 | – | – | – | – | – | 11.5 | – | 27.0 |
| Company “Averyanovka” | – | 51.4 | 48.2 | – | – | – | – | – | – | 50.8 |
| Company “Agrofirma “Molochnik” | 22.5 | – | – | – | – | – | – | – | – | 22.5 |
| Open joint-stock company “Marenevka” | – | 64.2 | – | – | – | – | – | – | – | 64.2 |
| Agricultural cooperative “Khizroeva” | 60.7 | 60.8 | 81.5 | – | – | 70.0 | – | 90.8 | 0 | 62.2 |
| Agricultural cooperative “Kolkhoz Krasny Partizan” | 76.1 | 90.5 | 92.3 | 0 | 94.2 | 0 | 69.7 | 93.0 | 0 | 77.3 |
| Scientific production association “Plemservice” | – | – | – | – | – | – | – | 76.7 | 0 | 27.1 |
| Agricultural cooperative plemkhoz “Urkarakhsky” | 2.0 | 0.5 | 0 | 0 | 0 | 0 | 15.8 | 7.8 | 7.6 | 1.8 |
| Collective farm “Agrofirma Chokh” | 38.4 | 13.6 | 52.8 | – | 38.9 | 48.0 | 64.7 | 61.3 | 64.9 | 48.0 |
| Agrofirma “Sogratl” | – | – | – | – | – | – | – | 45.4 | 36.9 | 40.9 |
| Agricultural cooperative “Agrofirma named after U. Buynaksky” | 34.5 | – | 0 | – | – | 0 | 24.9 | 55.8 | 26.9 | 35.3 |
| Agricultural cooperative “Novochirkeysky” | 58.3 | – | – | – | – | – | – | – | 40.0 | 53.1 |
| Agricultural cooperative “Plemkhoz Kulinsky” | 11.7 | 14.0 | – | 21.4 | 14.7 | – | 1.9 | 0 | 0 | 6.5 |
| Agricultural cooperative “Plemkhoz named after B. Aminov” | – | 14.3 | – | 8.2 | – | 4.8 | 2.0 | 1.9 | 2.2 | 6.8 |
| Joint-stock company “Darada-Murada” | 52.7 | 79.1 | 58.5 | 0 | 20.0 | – | 62.4 | – | – | 51.6 |
| Worker cooperative “Murad” | – | 68.5 | – | 34.2 | – | – | 35.3 | 8.2 | 24.0 | 41.2 |
| Municipal unitary enterprise named after Kirov | 0 | 0 | 0.6 | – | – | – | – | – | – | 0.2 |
| Agricultural cooperative “Druzhba” | 12.7 | 49.5 | 32.1 | – | 2.2 | 3.6 | 0 | 13.0 | 9.4 | 15.5 |
| Agricultural cooperative “Novaya Zhizn” | – | 25.4 | 21.9 | 22.0 | 18.9 | 21.6 | 21.8 | 16.3 | 32,.8 | 23.1 |
| Governmental unitary enterprise “Dylymskoye” | 0 | 40.3 | 14.8 | 0.3 | 6.9 | 1.4 | 0 | 1.7 | 0 | 8.5 |
| Company “Vympel-1” | – | – | – | – | – | – | – | – | 0 | 0 |
| Agricultural cooperative “Agrofirma Sivukh” | – | 0 | 0 | 0 | – | 0 | – | – | – | 0 |
| Agricultural cooperative “Named after A. Daniyarov” | 0 | 0 | 0 | – | 0 | – | 0 | – | 0 | 0 |
| Municipal unitary agricultural enterprise “Talovka” | 0 | 84.8 | 38.3 | – | – | – | – | – | – | 42.2 |
| Family operated farm “Boztorgay” | – | – | – | 0 | – | 0 | 0.6 | – | 0 | 0.1 |
| Company “Kurbanservice” | – | – | – | – | 0.7 | – | 0 | 0 | 0 | 0.1 |
| Company “OORKh «Dagestanskoye” | – | – | 72.9 | – | 81.8 | – | 0 | – | – | 46.1 |
| Total for the year, % | 29.0 | 37.1 | 35.1 | 7.2 | 18.3 | 10.1 | 22.6 | 23.2 | 13.5 | 23.6 |
Over the nine-year period, 33,838 animals were tested using the AGID-test, of which 7,977 (23.6%) were seropositive for BLV. Furthermore, hematological examination of 1,950 cows confirmed a BL diagnosis in 606 individuals (31.1%).
BLV infection rates on breeding farms remained persistently high. The lowest number of virus-carriers in animals was reported in 2012 – 7.2%, in other years it ranged from 10.1 to 37.1%. Similarly, the proportion of animals with BL, as determined by hematological tests, remained elevated, fluctuating between 15.9 and 67.5%.
It was established that breeding farms company “Vympel-1”, agricultural cooperative “Agrofirma Sivukh”, agricultural cooperative “Named after A. Daniyarov” were free from BL; on family operated farm “Boztorgay”, company “Kurbanservice”, municipal unitary enterprise named after Kirov, Agricultural cooperative plemkhoz “Urkarakhsky”, agricultural cooperative “Plemkhoz Kulinsky”, agricultural cooperative “Plemkhoz named after B. Aminov”, governmental unitary enterprise “Dylymskoye”, the infection rate did not exceed 10%; on agricultural cooperative “Druzhba”, company “Agrofirma “Molochnik”, agricultural cooperative “Novaya Zhizn”, company “Plempredpriyatiye Elita”, scientific production association “Plemservice” the infection rate ranged from 10 to 30%, on the remaining breeding farms the infection rate ranged from 35.3 to 77.3% (Fig. 3).
Fig. 3. The BLV infection rate on the breeding farms in the Republic of Dagestan in 2009–2017 (%)
In 2009, BL restrictions were officially imposed on 17 farms, 9 of which were breeding farms. By 2013, one additional breeding farm was identified as affected, while health status of animals on 2 farms was improved. However, for a prolonged period (as of January 1, 2019), a significant number of breeding farms remained BLV-positive (agricultural cooperative “Agrofirma named after U. Buynaksky”, agricultural cooperative “Kolkhoz Krasny Partizan”, scientific production association “Plemservice”, agricultural cooperative “Plemkhoz Kulinsky”, agricultural cooperative “Plemkhoz named after B. Aminov”, agricultural cooperative “Druzhba”, governmental unitary enterprise “Dylymskoye”, agricultural cooperative “Novaya Zhizn”) [
When assessing the disease situation, it is important to note that leukosis intensity varied significantly across breeding farms in the Republic of Dagestan. The disease’s widespread persistence is attributed to several key factors: the long-standing infection on these farms, a lack of comprehensive control measures, and insufficient diagnostic coverage. From 2009 to 2017, serological testing rates remained critically low, at only 17.5–21.6%.
It should be noted that the number of breeding farms in the region often varied depending on the disease situation. Due to BL restrictive measures, some breeding farms were converted to commercial farms.
Thus, a tense situation regarding BLV persisted in the region’s breeding farms until 2017. The presence of hematologically BL-diseased animals and BLV-infected animals was confirmed in almost all breeding herds. In fact, with the exception of agricultural cooperatives “Plemkhoz Kulinsky” and “Plemkhoz named after B. Aminov” in the highland zone, all other breeding farms were affected by leukosis.
The most valuable cattle gene pool in Dagestan is concentrated on breeding farms where leukosis infection was also was also widespread. Therefore, in the following years, the primary task for the regional veterinary service became the health improvement on breeding farms from leukosis infection.
This was particularly critical as these farms concentrated Dagestan’s most valuable cattle gene pool. Consequently, the regional veterinary service prioritized the improvement of animal health on these breeding farms from leukosis.
A large-scale, systematic effort began with the adoption of the “Bovine Leukosis Prevention and Control Action Plan in the Republic of Dagestan”4 and the subprogram “Prevention and Eradication of Bovine Leukosis on Farms in the Republic of Dagestan” under a republican target program5, which has been extended through the current year. The health improvement strategy on BL-affected farms (herds) involves culling and sending for slaughter of all seropositive animals identified during routine laboratory testing.
It should be noted that since 2019, serological testing has covered nearly the entire susceptible cattle population on breeding farms. The resulting trend of reduced BLV infection from 2018 to 2024 is presented in Table 2 and Figure 4.
Table 2
Serological testing of cattle for BL on the breeding farms in the Republic of Dagestan in 2018–2024
* No. (breeding farms): 1 – joint-stock company “Kizlyaragrocomplex”, 2 – joint-stock company “Darada-Murada”, 3 – worker cooperative “Murad”, 4 – collective farm “Agrofirma Chokh”, 5 – agrofirma “Sogratl”, 6 – agricultural cooperative “Kolkhoz Krasny Partizan”, 7 – agricultural cooperative “Alkhas Kuli”, 8 – scientific production association “Plemservice”, 9 – agricultural cooperative “Plemkhoz Kulinsky”, 10 – agricultural cooperative “Plemkhoz named after B. Aminov”, 11 – agricultural cooperative “Agrofirma named after U. Buynaksky”, 12 – company “Kurbanservice”, 13 – agricultural cooperative “Novaya Zhizn”, 14 – governmental unitary enterprise “Dylymskoye”, 15 – agricultural cooperative “Druzhba”, 16 – company “Vympel-1”, 17 – company “Averyanovka”, 18 – agricultural cooperative “Novochirkeysky”, 19 – agricultural cooperative plemkhoz “Urkarakhsky”, 20 – agricultural cooperative “Khizroeva”, 21 – family operated farm “Iman”, 22 – agricultural cooperative “Ulluchai”, 23 – agricultural cooperative “Mesed”, 24 – agricultural artel “Otgonnik”, 25 – family operated farm “Kosulya”, 26 – agricultural cooperative “Agrofirma-Tsovkra-2”, 27 – company “Chirkeysky ecoproduct”, 28 – company “Chokh-Agroproduct”; “+” – number of animals infected with BLV; “–” – no data on the status of the breeding farm.
| No. item | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | ||||||||||||||
| tests | + | % | tests | + | % | tests | + | % | tests | + | % | tests | + | % | tests | + | % | tests | + | % | |
| 1 | 2,474 | 705 | 28.5 | 6,633 | 488 | 7.4 | 6,062 | 128 | 2.1 | 6,192 | 98 | 1.6 | 2,449 | 216 | 8.8 | 470 | 13 | 2.8 | 619 | 11 | 1.8 |
| 2 | 51 | 34 | 66.7 | 851 | 29 | 3.4 | 1,221 | 255 | 20.9 | 813 | 78 | 9.6 | 2,264 | 23 | 1.0 | 1,548 | 0 | 0 | – | – | – |
| 3 | – | – | – | 150 | 91 | 60.7 | 533 | 1 | 0.2 | 807 | 70 | 8.7 | 1,223 | 37 | 3.0 | 1,457 | 0 | 0 | – | – | – |
| 4 | 422 | 18 | 4.3 | 1,927 | 96 | 5.0 | 1,505 | 83 | 5.5 | 2,017 | 63 | 3.1 | 1,383 | 20 | 1.4 | 1,295 | 0 | 0 | 1,377 | 0 | 0 |
| 5 | 511 | 102 | 20.0 | 1,067 | 83 | 7.8 | 1,273 | 51 | 4.0 | 1,751 | 77 | 4.4 | 831 | 46 | 5.5 | 897 | 0 | 0 | 1,457 | 0 | 0 |
| 6 | 144 | 5 | 3.5 | 785 | 4 | 0.5 | 415 | 8 | 1.9 | 492 | 4 | 0.8 | 520 | 11 | 2.1 | 660 | 0 | 0 | 510 | 0 | 0 |
| 7 | 58 | 1 | 1.7 | 130 | 1 | 0.8 | 158 | 3 | 1.9 | 232 | 3 | 1.3 | 130 | 0 | 0 | 623 | 0 | 0 | – | – | – |
| 8 | 67 | 22 | 32.8 | 197 | 0 | 0 | 365 | 0 | 0 | 526 | 0 | 0 | 778 | 20 | 2.6 | – | – | – | 350 | 0 | 0 |
| 9 | 640 | 28 | 4.4 | 1,131 | 83 | 7.3 | 1,376 | 0 | 0 | 1,115 | 9 | 0.8 | 1,534 | 0 | 0 | 1,553 | 0 | 0 | 1,060 | 0 | 0 |
| 10 | 361 | 7 | 1.9 | 630 | 5 | 0.8 | 700 | 9 | 1.3 | 315 | 3 | 1.0 | 553 | 0 | 0 | 553 | 0 | 0 | 580 | 0 | 0 |
| 11 | 1,009 | 71 | 7.0 | 2,028 | 18 | 0.9 | 1,167 | 0 | 0 | 1,192 | 0 | 0 | 1,171 | 0 | 0 | 1,643 | 0 | 0 | 1,646 | 0 | 0 |
| 12 | 1,010 | 0 | 0 | 890 | 0 | 0 | 1,185 | 0 | 0 | 1,368 | 0 | 0 | 1,667 | 0 | 0 | 1,809 | 0 | 0 | 2,005 | 0 | 0 |
| 13 | 221 | 44 | 19.9 | 306 | 50 | 16.3 | 363 | 57 | 15.7 | 172 | 0 | 0 | – | – | – | – | – | – | – | – | – |
| 14 | 161 | 5 | 3.1 | 395 | 2 | 0.5 | 196 | 5 | 2.6 | 180 | 0 | 0 | – | – | – | – | – | – | – | – | – |
| 15 | 250 | 31 | 12.4 | 317 | 50 | 15.8 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
| 16 | – | – | – | 942 | 4 | 0.4 | 905 | 0 | 0 | 875 | 0 | 0 | 1,002 | 0 | 0 | 1,045 | 0 | 0 | 1296 | 0 | 0 |
| 17 | 199 | 49 | 24.6 | 506 | 49 | 9.7 | 403 | 0 | 0 | 65 | 0 | 0 | – | – | – | – | – | – | – | – | – |
| 18 | 198 | 38 | 19.2 | 565 | 2 | 0.4 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
| 19 | 114 | 9 | 7.9 | 243 | 2 | 0.8 | – | – | – | – | – | – | – | – | – | 267 | 0 | 0 | 271 | 0 | 0 |
| 20 | 168 | 5 | 3.0 | 830 | 6 | 0.7 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
| 21 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | 505 | 0 | 0 | 1054 | 0 | 0 |
| 22 | – | – | – | – | – | – | 86 | 0 | 0 | 270 | 0 | 0 | 114 | 0 | 0 | 126 | 0 | 0 | 140 | 0 | 0 |
| 23 | – | – | – | – | – | – | 353 | 1 | 0.3 | 555 | 2 | 0.4 | 767 | 0 | 0 | 1,768 | 0 | 0 | 832 | 0 | 0 |
| 24 | – | – | – | – | – | – | – | – | – | – | – | – | 280 | 0 | 0 | 344 | 0 | 0 | 419 | 0 | 0 |
| 25 | – | – | – | – | – | – | – | – | – | – | – | – | 261 | 0 | 0 | 320 | 0 | 0 | – | – | – |
| 26 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | 253 | 0 | 0 |
| 27 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | 756 | 0 | 0 |
| 28 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | 230 | 0 | 0 |
| Total number | 8,058 | 1,174 | 14.6 | 20,523 | 1,063 | 5.2 | 18,266 | 601 | 3.3 | 18,937 | 407 | 2.1 | 16,927 | 373 | 2.2 | 16,883 | 13 | 0.1 | 14,855 | 11 | 0.1 |
Fig. 4. Dynamics of BLV infection on the breeding farms in the Republic of Dagestan in 2018–2014
Over the seven-year period, state veterinary service laboratories tested 114,449 blood serum samples using the AGID test obtained from 28 regional operational breeding farms, revealing an average infection rate of 3.2%. Hematological testing for BLV-infected animals has been discontinued, as all BLV-infected animals are now sent for immediate slaughter without being held over.
Analysis of infection dynamics confirms a consistent downward trend in BLV infection rate among susceptible animals (Fig. 4). Specifically, the infection rate (carrier state) among the tested livestock dropped from 14.6% in 2018 to 5.2% in 2019, 3.3% in 2020, 2.1% in 2021, 2.2% in 2022, and 0.1% in 2023. This progress was sustained in 2024, with only 11 AGID-positive animals (0.1%) detected out of 14,855 tested, underscoring the stability and efficacy of the control measures implemented on the breeding farms in the Republic of Dagestan. The BLV-infected animals were traced to a single source: company “Plempredpriyatiye Elita”, a subsidiary of joint-stock company ”Kizlyaragrocomplex”.